Jay, I'm not speaking for Spamhaus or 1&1 here, but some hosting providers do outbound spam detection, and treat outbound mail that they believe is spammy in a different way than their customers' less suspicious outbound mail. In 1&1's case, it appears that they route the suspicious outbound mail via IPs that they've reserved for this purpose. Receivers can then set up a policy for how to treat that suspicious mail. I presume 1&1 asked Spamhaus to list those special-purpose outbound IPs as a courtesy.
Microsoft Office 365 takes a similar approach and tags suspicious outbound messages with a header that identifies them as suspect. Paul Kincaid-Smith EmailGrades On Wed, Feb 14, 2018 at 11:12 AM, Jay Hennigan <mailop-l...@keycodes.com> wrote: > On 2/14/18 9:47 AM, Paul Kincaid-Smith wrote: > >> Hi Scott, >> >> Spamhaus lists that IP as a "courtesy SBL listing" -- presumably at the >> request of the IP's owner. Here are other IPs Spamhaus lists as a courtesy: >> >> https://www.spamhaus.org/sbl/listings/courtesy.spamhaus.org >> > > So how exactly does that work? The address holder contacts Spamhaus and > says something like, "Hello, Spamhaus. I'm a notorious and deliberate > spammer and plan on sending several metric tons of spam from the following > IPs. Could you please list these IPs as a courtesy to my potential victims? > OK thanks, bye" and then they do so? > > -- > Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net > Impulse Advanced Communications - http://www.impulse.net/ > Your local telephone and internet company - 805 884-6323 - WB6RDV > > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop >
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